The invention relates to automotive engine test equipment having a plurality of test leads which are connectable to an engine for monitoring particular operating conditions of the engine in order to provide a visual display indication to the mechanic operator as to the analysis of the operating condition of the engine, and more particularly relates to circuitry utilized to indicate to the operator when a particular test lead of the engine test equipment has become disconnected from the engine.
The servicing of vehicle engines is becoming increasingly important because of road safety considerations and public awareness of automotive emissions on the environment. In addition, the engines of current vehicles are becoming more difficult and complicated to diagnose and analyze.
Much of the test equipment which is available on the market utilizes several test leads which are connected to the engine for retrieving certain data information. In certain cases the particular information to be monitored will be a voltage level lying within a predetermined voltage range. In the event that the test lead was not properly connected to the automotive engine, a zero voltage ordinarily appears, which zero voltage may lie within the predetermined voltage range. In some cases, as for example measuring distributor points drop, the voltage sought after is zero volts.
In such cases, where a zero or near zero voltage reading is obtained, the operator cannot be sure that a lead connection is improperly made or that an accurate voltage condition is actually being sensed. Thus, erroneous conclusions may be drawn.
Therefore, it is an object of the present invention to provide an automotive engine analyzer in which the operator is visually instructed that a test lead has become disconnected from the automotive engine.
It is a further object of the present invention to provide apparatus for generating a non-zero voltage level falling outside of the range of valid test data signals, whenever a lead becomes disconnected from the engine.